Definition of Cell Theory

At present, the scientific community agrees with a fully consolidated idea: the cell is the fundamental unit of life in any of its dimensions. In this way, all known beings come from an original cell that, in turn, comes from the union of two cells that have separated from the body of the parents. Thus, in a cell "it is written" how a new being of nature is going to be.

The theory mobile it was a somewhat late explanation, since it appeared in the first decades of the nineteenth century. Its creators were the German scientists Schleiden and Schwann, who presented the cellular conception after a long debate in which an attempt was made to give a convincing explanation of the origin of life. These two biologists realized a significant fact: a nucleus with identical characteristics appeared in plant and animal cells. This discovery meant finding a link between all living beings.

The road to a new theory

The cell theory replaced a previous conception: the theory of spontaneous generation, according to which life was generated spontaneously from things that were not alive. It must be remembered that the understanding of the cell was only possible after the introduction of the

microscope (It was the Englishman Robert Hooke who discovered the first cells observing cork in the eighteenth century).

Subsequently, the Dutch biologist Leeuwenhoke observed red and white blood cells and sperm under the microscope (the observation of sperm meant that the reproduction of mammals). Hooke and Leeuwenhoek's research facilitated Schleiden and Schwann's novel approach. Years later, Robert Virchow presented a series of tests to establish the cell theory and definitively banish the theory of spontaneous generation.

Main characteristics of the cell theory

The cell is a tiny living being that represents life. The cell theory has three fundamental principles:

1) the cell is the structural unit of any life form,

2) the cell is the functional and physiological unit of life (there is a metabolism in its interior that determines its later development) and

3) the cell is the unit of origin of what we understand by life.

The implications of the cell theory go beyond the simple structural explanation of cells in their classical division between eukaryotes and prokaryotes, since the cell theory represented a definitive step towards the understanding of chromosomes and the mechanisms of the inheritance and had repercussions on the botany, in zoology, in evolution of species and, ultimately, in all disciplines that make up biology.

The cell theory allows, in a few words, to explain and understand the most relevant aspect of the entire universe: life itself.

Photos: iStock - cogal / Xavier Arnau

Topics in Cell Theory